Near-Infrared Classification of a and F Stars.

Abstract

view Abstract Citations (29) References (6) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Near-Infrared Classification of a and F Stars. Parsons, Sidney B. Abstract Infrared spectra ( A) of numerous MK standards at a dispersion of 200 A/mm have been examined for criteria of visual two-dimensional classification It is apparent that luminosities can be determined more accurately from these spectra than from similar spectra in the violet region, while spectral types are more difficult to assign. In particular, lines of oxygen and hydrogen are powerful luminosity indicators in A- and F-type stars. Quantitative measurements show that 0 1 7774 is extremely strong (E.W. 2 A) in supergiants, so that the presence or absence of this line on 850 A/mm objective-prism spectra will provide a rapid means of distinguishing between A and F stars of type Ia and other stars. While the oxygen line differs little between giants and dwarfs, the central depth of the blend of Ca ii (X 8542) and P 15 (X 8545) was found to be directly proportional to absolute magnitude, for a given spectral type, and, when plotted against P 14 (X 8598), allows the absolute magnitude and spectral type to be determined unambiguously. Publication: The Astrophysical Journal Pub Date: October 1964 DOI: 10.1086/147990 Bibcode: 1964ApJ...140..853P full text sources ADS | data products SIMBAD (28)